Electric insulation for metal pipes



July 13 1926.,

A. M. BOYD ELECTRIC INSULATION FQR METAL PIPEs Filed July 1o, I 1924 'lV/Miss:

Patented July 13, 1926. y UNITED `STATES PATENT OFFICE.

ALEERT M. EoYD, oP PHILADELPHIA, PENNSYLVANIA, AssIeNoR ToTHE U.A G. 1. CONTRACTING COMPANY, oP PHILADELPHIA, PENNSYLVANIA, A coRPoRATIoN `or DELAWARE.

ELECTRIC INSULATION FOR METAL PIPES.

Application filed July 10, 1924. Serial N'o. 725,267.

rl`he principal object of the present invention is to prevent or oppose the deterioratlon of steel mains or metal pipes through electrolysis. Another object of the invent1on is to provide an etiicient, durable and reliable electric insulation for sections of steel mains or metal pipes.

Other objects of the invention will appear lfrom the following description and the invent-ion will be claimed at the end hereof but, generally stated, it may be said to -comprise a pair of tubular metal elements adapted for insertion in aV pipe line and having integral confronting end flanges between which there is arranged a metal faced electrically insulating washer,V together with a metal clamp mounted on said elements and provided with electrically insulated bolts spaced clear of said washer and adapted for drawingthe end flanges up' toV said metal faced Washer or gasket.v

In the following description reference will be made to the accompanying drawing forming part hereof andl in which the single figure is a longitudinalsectional view of so 'much of electric insulation for metal pipes as is necessary for an illustration of the invention.

In the drawing 1 and 2 are a pair of tubu# lar metal elements of-which parts only are shown for lack of room on the sheet and they are adapted for insertion in a pipe line. These elements are provided with end flanges 3 and 4 arranged in spaced confronting relation. The confronting surfaces of these flanges-may be machined or otherwise finished or faced. 5 and 6 are, clamp rings mounted on -the elements 1 and 2, and they engage the flanges 3 and 4. There is a set of washers or gaskets interposed between the faces of the flanges 3 and 4, and of this setv the libre Vwasher or gasket 7 is of electrically insulating material, and the outside washers or gaskets 8 are of lead or. like soft metal and they serve to insure continuity and tightness of the iiuidway. Bolts 9 engage the clamp rings and are adapted to draw them towards each other. `As shown the -bolts are spaced clear f the rim of the washer 7, and the washer is wider than the washers 8, and the washer 7 extends both inward and outward beyond the washers 8. 10 are thimbles of electrically Insulating material and theyr enclrcle the bolts.

.is 'strong and durable.

and extend through the bolt holes provided in the clamp rings.v A pair of wash'ers 11 and 12 are arranged between the rings 5 and 6, and the bolt. Of these washers the one, 11, next the ring is of electrically insulating material, and the other washer 12, is of lne-tal and is smaller than the washer 11. The thimbles 10 are spaced at`their inner ends so that they in no way interfere with the drawing up of the clamp.

It will be observed that the elements 1 and 2 are thoroughly electrically insulated from each other. The insulating gasket 7 can well be made of appropriate Vsize for strength and durability, and the lead or soft metal gaskets 8 while providing a tight joint also protect the insulating washer 7. Inasmuch as the insulating washers 7 and 11 project beyond' the adjacent metallic washers they provide an extended insulating surface. Asa whole the electric insulation It will be understoodthat the tubular metal elements 1 and 2 are inserted in'to a pipe line of steel welded or screwed mains. The mains and the welding or screwing are not shown because they are too well understood to require illustration and moreover there is not suiicient room on the sheet. Electrolysis which causes deterioration in pipe lines and mains involves a conducting path forV the flow of electric current and by the insertion of the Vdescribed insulation at intervals in the line -of pipe or main no such path is provided and consequently deterioration by electrolysis is avoided.

It will be obvious to those skilled in the art to which the invention relates that modications may be made in details of construction and arrangement without departing "from the spirit of the invention -which is not limited as to those matters or otherwise than as the prior art and the appended claims may require. Y

I claim: l 1.- Electric insulation for metal pipes comprising a pair of tubular metal elements adapted for insertion in a pipe line and having integral end ilanges arranged in spaced confronting relation,clamp rings mountedv on said elements and engaging said flanges, a set of washers or gaskets lnterposed between the faces of said flanges and whereof the middle 911e is 0f electrically insulating the rings, and a pair of washers between each of the rings' and the bolts and vof which the one next the ring is of insulating material and of which the other is of metal.

2. Electric insulation for metal pipesy comprising a pair of tubular metal elements having integral end flanges, a metal faced electrically insulating washer interposed between sai'd fianges, and a metal clamp mounted on said elements and engagin the end anges and provided with insu ated bolts spaced clear of the washer for drawing the end 'anges up to the metal faces of the washer.

ALBERT M. BOYD. 

